Primary HIV-1 infection is a period of explosive viral growth in which critical lymphoid organs are seeded and in which the initial movement toward viral diversity is established. The mergence of a multifaceted humoral and cellular immune response is associated with a rapid decline in plasma levels of HIV-1 RNA but virus is not eliminated from the host. Initial events in the virus/host interactions clearly play a critical role in limiting viral replication and in determining the subsequent natural history f the illness. Viral and/or immunologic factors that permit the virus to evade elimination have not yet been delineated. Emerging data suggest that antiretroviral intervention during primary infection may have profound implications for the virus/host interaction. It has been suggested that this interval during which viral diversity is relatively limited and in which viral seeding of lymphoid organs is still incomplete may be a time during which potent antiretroviral chemotherapy might even eliminate virus from the host. We have assembled a group of laboratory-based and clinical investigators who wish to intensively characterize viral and immunologic events during primary infection in the context of therapeutic interventions with maximally active antiretroviral regimens. These investigations will provide additional insights into the immunopathogenesis of HIV-1 infection and will have important implications for designing antiretroviral chemotherapeutic strategies and for AIDS vaccine development.